Cross-compile GNU assembler for MIPS
by Wojciech Adam Koszek ⋅ Jun 10, 2012 ⋅ East Palo Alto, CATechnical post which you'll find useful if you study the details of the MIPS architecture, maybe from Patterson and Hennessy books.
Just a short note, not to have to walk through the Web each time I want to get some strange opcodes generated.
Today “strange” means “MIPS”. “Nobody uses MIPS”, you say? Well – I still believe MIPS is the cleanest RISC architecture available today. So yes, I want to have something translate:
_start:
addi $2, $2, 123
addi $3, $3, 321
add $4, $2, $3
addi $5, $5, 1
addi $6, $6, 2
or $7, $5, $6
addi $8, $8, 0xf
addi $9, $9, 0x3
and $10, $8, $9
To:
0x2042007b
0x20630141
0x00432020
0x20a50001
0x20c60002
0x00a63825
0x2108000f
0x21290003
0x01095024
For me. So first let me present steps for building the GNU assembler for MIPS. Steps:
wget ftp://sourceware.org/pub/binutils/snapshots/binutils-2.22.52.tar.bz2
tar xjf binutils-2.22.52.tar.bz2
cd binutils-2.22.52
mkdir build
../configure --target=mips --prefix=${HOME}/bin/mips
make
make install
set path=($path ${HOME}/bin/mips/bin)
Now that I have MIPS assembler, I have created a simple makefile for myself, which translates opcodes from generated object file to hexadecimal opcodes:
imem.hex: imem.s
mips-as -o imem.o imem.s
mips-objcopy -O binary imem.o imem.bin
mips-objdump -d imem.o > imem.dump
sed '1,7d' imem.dump | awk '{ print "0x"$$2 }' > imem.hex
Thanks to these several steps, I have a simple infrastructure to play with MIPS opcodes.